Mission Rubber 105664 MR56 64 Flex-Seal Coupling, 6-Inch Plastic/Cast-Iron to 4-Inch Plastic/Cast-Iron Flexibility - Sleeve is manufactured of molded natural and synthetic rubber Leakproof Seal - Inside surfaces of transitional size couplings are stepped to conform better to different pipe sizes Side A: 6.45-Inch, Side B: 4.36-Inch, Length: 6-Inch Corrosion Resistant - Use of stainless steel clamping bands are highly effective in a variety of environments 313 Series Marine Grade Stainless Steel conforms to ASTM A 240